Battery module compressed cell assembly

ABSTRACT

The present disclosure relates to a stacked cell manufacturing scheme for battery modules. A disclosed method of manufacturing a battery module includes assembling a plurality of prismatic battery cells of the battery module into a cell stack. The method includes compressing the cell stack using an actuating clamping mechanism, inserting the cell stack into a housing of the battery module with the actuating clamping mechanism engaged with and compressing the cell stack, and removing the actuating clamping mechanism from the cell stack. The housing of battery module maintains a compression of the cell stack above a predetermined threshold in the battery module after removing the actuating clamping mechanism.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation Application of U.S. patentapplication Ser. No. 14/501,241, entitled “BATTERY MODULE COMPRESSEDCELL ASSEMBLY,” filed Sep. 30, 2014, which is hereby incorporated byreference in its entirety for all purposes.

BACKGROUND

The present disclosure relates generally to the field of batteries andbattery modules. More specifically, the present disclosure relates to astacked cell manufacturing scheme for battery modules.

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described below. This discussion is believed to be helpful inproviding the reader with background information to facilitate a betterunderstanding of the various aspects of the present disclosure.Accordingly, it should be understood that these statements are to beread in this light, and not as admissions of prior art.

A vehicle that uses one or more battery systems for providing all or aportion of the motive power for the vehicle can be referred to as anxEV, where the term “xEV” is defined herein to include all of thefollowing vehicles, or any variations or combinations thereof, that useelectric power for all or a portion of their vehicular motive force. Forexample, xEVs include electric vehicles (EVs) that utilize electricpower for all motive force. As will be appreciated by those skilled inthe art, hybrid electric vehicles (HEVs), also considered xEVs, combinean internal combustion engine propulsion system and a battery-poweredelectric propulsion system, such as 48 Volt (V) or 130V systems. Theterm HEV may include any variation of a hybrid electric vehicle. Forexample, full hybrid systems (FHEVs) may provide motive and otherelectrical power to the vehicle using one or more electric motors, usingonly an internal combustion engine, or using both. In contrast, mildhybrid systems (MHEVs) disable the internal combustion engine when thevehicle is idling and utilize a battery system to continue powering theair conditioning unit, radio, or other electronics, as well as torestart the engine when propulsion is desired. The mild hybrid systemmay also apply some level of power assist, during acceleration forexample, to supplement the internal combustion engine. Mild hybrids aretypically 96V to 130V and recover braking energy through a belt or crankintegrated starter generator. Further, a micro-hybrid electric vehicle(mHEV) also uses a “Stop-Start” system similar to the mild hybrids, butthe micro-hybrid systems of a mHEV may or may not supply power assist tothe internal combustion engine and operates at a voltage below 60V. Forthe purposes of the present discussion, it should be noted that mHEVstypically do not technically use electric power provided directly to thecrankshaft or transmission for any portion of the motive force of thevehicle, but an mHEV may still be considered as an xEV since it does useelectric power to supplement a vehicle's power needs when the vehicle isidling with internal combustion engine disabled and recovers brakingenergy through an integrated starter generator. In addition, a plug-inelectric vehicle (PEV) is any vehicle that can be charged from anexternal source of electricity, such as wall sockets, and the energystored in the rechargeable battery packs drives or contributes to drivethe wheels. PEVs are a subcategory of EVs that include all-electric orbattery electric vehicles (BEVs), plug-in hybrid electric vehicles(PHEVs), and electric vehicle conversions of hybrid electric vehiclesand conventional internal combustion engine vehicles.

xEVs as described above may provide a number of advantages as comparedto more traditional gas-powered vehicles using only internal combustionengines and traditional electrical systems, which are typically 12Vsystems powered by a lead acid battery. For example, xEVs may producefewer undesirable emission products and may exhibit greater fuelefficiency as compared to traditional internal combustion vehicles and,in some cases, such xEVs may eliminate the use of gasoline entirely, asis the case of certain types of EVs or PEVs.

As technology continues to evolve, there is a need to provide improvedpower sources, particularly battery modules, for such vehicles. In sometraditional configurations, the battery cells of a battery module aretightly packed and maintained within the battery housing with anattached clamping mechanism to, for example, maximize energy density ofthe battery module. Traditional clamping mechanisms often includeexternal features of the battery module (e.g., to facilitate access tothe clamping mechanism for manufacture) and are activated after all ofthe battery cells have been positioned within the battery module. It isnow recognized that such clamping mechanisms can add bulk, weight, andsome complexity to the battery module and assembly process.

It is further recognized that, in certain systems, differences in thethickness between battery cells as a result of manufacturing variabilitycan prove problematic when positioning the battery cells within thebattery housing. Accordingly, it is now recognized that enhancements tosuch battery module manufacturing processes, battery modulereproducibility, and so forth, may be desirable by providing mechanismsfor arranging the battery cells within the battery housing that allowgreater variability in the dimensions of each battery cell, while stillenabling a desired degree of compression/clamping.

SUMMARY

A summary of certain disclosed herein is set forth below. It should beunderstood that these aspects are presented merely to provide the readerwith a brief summary of these certain embodiments and that these aspectsare not intended to limit the scope of this disclosure. Indeed, thisdisclosure may encompass a variety of aspects that may not be set forthbelow. The present disclosure relates to batteries and battery modules.More specifically, the present disclosure relates to lithium ion batterycells that may be used in vehicular contexts (e.g., xEVs) as well asother energy storage/expending applications (e.g., energy storage for anelectrical grid).

The present disclosure relates to a battery module includes a housingincluding a first interior surface and a second interior surfaceopposite the first interior surface. The battery module also includes acompressed cell assembly disposed within an interior space of thehousing between the first and second interior surfaces. The compressedcell assembly includes a plurality of prismatic battery cells arrangedin a cell stack that includes a first end and a second end opposite thefirst end. The compressed cell assembly also includes a retaining walldisposed between the first end of the cell stack and the first interiorsurface of the housing. The retaining wall includes a first surface incontact with the first end of the cell stack. The retaining wall alsoincludes a second surface opposite the first surface that contacts thefirst interior surface of the housing. The first and second interiorsurfaces are configured to maintain the compressed cell assembly in acompressed state having a compression force above a predeterminedthreshold.

The present disclosure also relates to a battery module includes ahousing including a first interior surface and a second interior surfaceopposite the first interior surface. The battery module also includes aplurality of prismatic battery cells disposed in an interior space ofthe housing of the battery module. The plurality of prismatic batterycells are arranged in a cell stack that includes a first end and asecond end. The battery module also includes a first retaining walldisposed between the first end of the cell stack and the first interiorsurface of the housing. Additionally, the battery module includes asecond retaining wall disposed between the second end of the cell stackand the second interior surface of the housing. The first and secondretaining walls are configured to compress the cell stack.

The present disclosure also relates to a method for manufacturing abattery module. The method includes assembling a plurality of prismaticbattery cells into a cell stack. The method also includes compressingthe cell stack into a compressed cell stack. Further, the methodincludes inserting the compressed cell stack within a housing of abattery module. Additionally, the method includes maintaining acompression force on the compressed cell stack using the housing.

DRAWINGS

Various aspects of the disclosure may be better understood upon readingthe following detailed description and upon reference to the drawings inwhich :

FIG. 1 is a perspective view of a vehicle (an xEV) having a batterysystem contributing all or a portion of the power for the vehicle, inaccordance with an embodiment of the present approach;

FIG. 2 is a cutaway schematic view of the xEV embodiment of FIG. 1, inthe form of a hybrid electric vehicle (HEV) having a battery module withcompression features configured in accordance with an embodiment of thepresent approach;

FIG. 3 is a front top perspective view of a battery module, inaccordance with an embodiment of the present approach;

FIG. 4 is an exploded perspective view of an embodiment of the batterymodule of FIG. 3, illustrating an arrangement of features used to form acompressed cell assembly, in accordance with an embodiment of thepresent approach;

FIG. 5 is a perspective view of an embodiment of a prismatic batterycell that may be a part of the compressed cell assembly of FIG. 4, inaccordance with an embodiment of the present approach;

FIG. 6 is a front top perspective view of the battery module of FIG. 3with a top cover removed and having a compressed cell assembly with tworetaining walls, in accordance with an embodiment of the presentapproach;

FIG. 7 is a right side perspective view of the battery module of FIG. 3with a housing removed and having a relay disposed on one of theretaining walls, in accordance with an embodiment of the presentapproach;

FIG. 8 is a left side perspective view of the battery module of FIG. 3with the housing removed and having electronics disposed on another ofthe retaining walls, in accordance with an embodiment of the presentapproach;

FIG. 9 is an exploded perspective view of an embodiment of the batterymodule of FIG. 3 including a single retaining wall used for compressionof multiple stacks of battery cells, in accordance with an embodiment ofthe present approach;

FIG. 10 is a perspective view of an embodiment of the battery module ofFIG. 9 and having a retaining wall, where electronics of the batterymodule are on the retaining wall and protrude through a partial openingof the housing, in accordance with an embodiment of the presentapproach;

FIG. 11 is a flow diagram illustrating an embodiment of a method formanufacturing a battery module having a compressed cell assembly, inaccordance with an embodiment of the present approach;

FIG. 12 is a partial schematic diagram of a system for manufacturing abattery module having a compressed cell assembly, the system including aclamping mechanism for compressing the compressed cell assembly, inaccordance with an embodiment of the present approach;

FIG. 13 is a schematic diagram of the battery module of FIG. 3 havingtwo retaining walls maintained in position by retaining tabs of thehousing of the battery module, in accordance with an embodiment of thepresent approach; and

FIG. 14 is a schematic diagram of a battery module and having tworetaining walls maintained in position by retaining tabs of the housing,where one of the retaining walls functions as an end portion of thehousing, in accordance with an embodiment of the present approach.

DETAILED DESCRIPTION

One or more specific embodiments will be described below. In an effortto provide a concise description of these embodiments, not all featuresof an actual implementation are described in the specification. Itshould be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

The battery systems described herein may be used to provide power tovarious types of electric vehicles (xEVs) and other high voltage energystorage/expending applications (e.g., electrical grid power storagesystems). Such battery systems may include one or more battery modules,each battery module having a housing and a number of battery cells(e.g., Lithium-ion (Li-ion) electrochemical cells) arranged within thehousing to provide particular voltages and/or currents useful to power,for example, one or more components of an xEV. As another example,battery modules in accordance with present embodiments may beincorporated with or provide power to stationary power systems (e.g.,non-automotive systems).

Present embodiments include physical battery module features, assemblycomponents, manufacturing and assembling techniques, and so forth, thatfacilitate the manufacture of battery modules and systems in a mannerthat may enable a wider tolerance of battery cell dimensions, a widerdegree of variability within that tolerance, and a potential reductionin size and weight of the battery modules and systems. Indeed, using theapproaches described herein, it may be possible to design certainadvanced battery modules (e.g., Li-ion battery modules) to have adesired form factor (e.g., dimensions corresponding to a traditionallead acid battery), without having to use actuating clamping mechanismsto compress the battery cells. Indeed, it is now recognized thatactuating clamping mechanisms, which are discussed in further detailbelow, may be altogether eliminated from a battery module using theretaining and compression features of the present disclosure. Suchelimination can reduce the complexity and cost associated with batterymodule manufacture.

Despite such complexity and cost, in traditional systems, actuatingclamping mechanisms that are integral with the module (e.g., the modulehousing) tend to be typical. This is because certain types of batterycells are susceptible to a greater degree of swelling in one directioncompared to another (e.g., as in certain prismatic or other similarlyshaped battery cells), and are clamped down to maintain desired energydensity and performance during operation (e.g., by maintaining thedegree of swelling of the battery cells to under a certain amount). Inparticular, prismatic battery cells may swell in a thickness directionand may be clamped down to reduce the swelling. Many traditionalactuating clamping mechanisms used to provide such clamping includeactuating components incorporated into (e.g., attached to, disposedwithin, or integrated with) the battery module that can potentially addconsiderable weight to the battery module and add complexity tomanufacturing. Such actuating clamping mechanisms are intended to denoteclamping mechanisms that are integral with the battery module (i.e.,retained with the battery module after manufacture), and that areactuatable within the battery module to produce a desired clamping forceagainst the battery cells.

For example, in one traditional manufacturing process, battery cells maybe placed in a housing of a battery module, and the battery cells maythen be compressed, for example against each other and/or against thehousing, by an actuating clamping mechanism (e.g., an external crankingor bolt mechanism). Such actuating clamping mechanisms may include, forexample, a clamp attached to the battery module, a movable platedisposed within the battery module housing that may be actuated (e.g.,using a crank, a clamp, an adjustable tie and bolt mechanism) to abutagainst the battery cells, or an adjustable tie and bolt mechanism usedto actuate components (e.g., outer or inner walls) of the battery modulehousing. These additional clamping steps can require additional time andequipment during manufacture, in addition to the bulky and/or heavyactuating clamping components. Indeed, because the actuating clampingcomponents should be robust, they are generally made from strong, heavymaterials (e.g., metals).

As will be described in more detail below, the present embodimentsinclude battery modules having battery cells arranged in a compressedstack, where the compressed stack is maintained within the batterymodule using the housing of the battery module itself. In certainembodiments, the housing may be used in combination with additionalspacing features that are simply placed against features of the housingto maintain the compressed state of the stack.

Again, the battery modules configured in accordance with presentembodiments may be employed in any number of energy expending systems(e.g., vehicular contexts and stationary power contexts). To facilitatediscussion, embodiments of the battery modules described herein arepresented in the context of advanced battery modules (e.g., Li-ionbattery modules) employed in xEVs. With the foregoing in mind, FIG. 1 isa perspective view of such a vehicle 10 (e.g., an xEV), which mayutilize a regenerative braking system. Although the following discussionin presented in relation to vehicles with regenerative braking systems,the techniques described herein are adaptable to other vehicles thatcapture/store electrical energy with a battery, which may includeelectric-powered and gas-powered vehicles.

It may be desirable for a battery system 12 to be largely compatiblewith traditional vehicle designs. Accordingly, the battery system 12 maybe placed in a location in the vehicle 10 that would have housed atraditional battery system. For example, as illustrated, the vehicle 10may include the battery system 12 positioned similarly to a lead-acidbattery of a typical combustion-engine vehicle (e.g., under the hood ofthe vehicle 10). Furthermore, as will be described in more detail below,the battery system 12 may be positioned to facilitate managingtemperature of the battery system 12. For example, in some embodiments,positioning a battery system 12 under the hood of the vehicle 10 mayenable an air duct to channel airflow over the battery system 12 andcool the battery system 12.

A more detailed view of the battery system 12 is described in FIG. 2. Asdepicted, the battery system 12 includes an energy storage component 14coupled to an ignition system 16, an alternator 18, a vehicle console20, and optionally to an electric motor 22. Generally, the energystorage component 14 may capture/store electrical energy generated inthe vehicle 10 and output electrical energy to power electrical devicesin the vehicle 10.

In other words, the battery system 12 may supply power to components ofthe vehicle's electrical system, which may include radiator coolingfans, climate control systems, electric power steering systems, activesuspension systems, auto park systems, electric oil pumps, electricsuper/turbochargers, electric water pumps, heated windscreen/defrosters,window lift motors, vanity lights, tire pressure monitoring systems,sunroof motor controls, power seats, alarm systems, infotainmentsystems, navigation features, lane departure warning systems, electricparking brakes, external lights, or any combination thereof. In thedepicted embodiment, the energy storage component 14 supplies power tothe vehicle console 20 and the ignition system 16, which may be used tostart (e.g., crank) the internal combustion engine 24.

Additionally, the energy storage component 14 may capture electricalenergy generated by the alternator 18 and/or the electric motor 22. Insome embodiments, the alternator 18 may generate electrical energy whilethe internal combustion engine 24 is running. More specifically, thealternator 18 may convert the mechanical energy produced by the rotationof the internal combustion engine 24 into electrical energy.Additionally or alternatively, when the vehicle 10 includes an electricmotor 22, the electric motor 22 may generate electrical energy byconverting mechanical energy produced by the movement of the vehicle 10(e.g., rotation of the wheels) into electrical energy. Thus, in someembodiments, the energy storage component 14 may capture electricalenergy generated by the alternator 18 and/or the electric motor 22during regenerative braking. As such, the alternator and/or the electricmotor 22 are generally referred to herein as a regenerative brakingsystem.

To facilitate capturing and supplying electric energy, the energystorage component 14 may be electrically coupled to the vehicle'selectric system via a bus 26. For example, the bus 26 may enable theenergy storage component 14 to receive electrical energy generated bythe alternator 18 and/or the electric motor 22. Additionally, the bus 26may enable the energy storage component 14 to output electrical energyto the ignition system 16 and/or the vehicle console 20. Accordingly,when a 12 volt battery system 12 is used, the bus 26 may carryelectrical power typically between 8-18 volts.

Additionally, as depicted, the energy storage component 14 may includemultiple battery modules. For example, in the depicted embodiment, theenergy storage component 14 includes a lithium ion (e.g., a first)battery module 28 and a lead-acid (e.g., a second) battery module 30,which each includes one or more battery cells. In other embodiments, theenergy storage component 14 may include any number of battery modules.Additionally, although the lithium ion battery module 28 and lead-acidbattery module 30 are depicted adjacent to one another, they may bepositioned in different areas around the vehicle. For example, thelead-acid battery module may be positioned in or about the interior ofthe vehicle 10 while the lithium ion battery module 28 may be positionedunder the hood of the vehicle 10.

In some embodiments, the energy storage component 14 may includemultiple battery modules to utilize multiple different batterychemistries. For example, when the lithium ion battery module 28 isused, performance of the battery system 12 may be improved since thelithium ion battery chemistry generally has a higher coulombicefficiency and/or a higher power charge acceptance rate (e.g., highermaximum charge current or charge voltage) than the lead-acid batterychemistry. As such, the capture, storage, and/or distribution efficiencyof the battery system 12 may be improved.

To facilitate controlling the capturing and storing of electricalenergy, the battery system 12 may additionally include a control module32. More specifically, the control module 32 may control operations ofcomponents in the battery system 12, such as relays (e.g., switches)within energy storage component 14, the alternator 18, and/or theelectric motor 22. For example, the control module 32 may regulateamount of electrical energy captured/supplied by each battery module 28or 30 (e.g., to de-rate and re-rate the battery system 12), perform loadbalancing between the battery modules 28 and 30, determine a state ofcharge of each battery module 28 or 30, determine temperature of eachbattery module 28 or 30, control voltage output by the alternator 18and/or the electric motor 22, and the like.

Accordingly, the control unit 32 may include one or processor 34 and oneor more memory 36. More specifically, the one or more processor 34 mayinclude one or more application specific integrated circuits (ASICs),one or more field programmable gate arrays (FPGAs), one or more generalpurpose processors, or any combination thereof Additionally, the one ormore memory 36 may include volatile memory, such as random access memory(RAM), and/or non-volatile memory, such as read-only memory (ROM),optical drives, hard disc drives, or solid-state drives. In someembodiments, the control unit 32 may include portions of a vehiclecontrol unit (VCU) and/or a separate battery control module.Furthermore, as depicted, the lithium ion battery module 28 and thelead-acid battery module 30 are connected in parallel across theirterminals. In other words, the lithium ion battery module 28 and thelead-acid module 30 may be coupled in parallel to the vehicle'selectrical system via the bus 26.

The lithium ion battery modules 28 may have any one of a variety ofdifferent shapes, sizes, output voltages, capacities, and so forth, andthe present disclosure is generally intended to apply to differentvariations of the shapes and sizes of the modules illustrated in thefigures. Keeping this in mind, FIG. 3 is a front top perspective view ofone embodiment of the battery module 28. To facilitate discussion of thebattery module 28 and the various assemblies and components thereof, a Zaxis 40 is defined as extending through the length of battery module 28,a Y axis 42 is defined as extending through the height of the batterymodule 28 (transverse to the length in a first direction), and an X axis44 is defined as extending through a width of the battery module 28(transverse to the length and the height).

The battery module 28 includes a first terminal 58 (e.g., a negativeterminal) and a second terminal 60 (e.g., a positive terminal) that maybe coupled to an electrical load (e.g., circuit) for providing power tothe xEV 10. In other embodiments, the battery module 28 may have morethan two terminals, for example, to provide different voltages fordifferent loads via connections across different terminal combinations.

The battery module 28 includes a housing 62 for packaging or containinga plurality of battery cells (FIG. 4) and other components of thebattery module 28. For example, as will be described in more detailbelow, the housing 62 may package a plurality of prismatic batterycells. The housing 62 may include two end portions 64 and 66 (e.g.,disposed along the Z axis 40), two side portions 68 and 70 (e.g.,disposed along the X axis 44), a top portion 72 (e.g., fitted with a topcover 73), and a bottom portion 74. The housing 62 may be metallic(e.g., made from steel, aluminum, or another suitable metal), may bepolymeric (e.g., polypropylene, acrylonitrile butadiene styrene (ABS), apolystyrene (PS), a polyimide (PI), or another suitable polymer orplastic or combination thereof), or any other suitable housing materialor combination of materials.

As mentioned above, the dimensions (e.g., length and width) of the base(e.g., the bottom portion 74) of the battery module 28 may be selectedto be similar to or exactly the same as that of a particular type oflead-acid battery (e.g., a particular battery group). The battery module28 may include any number of battery cells, depending on the voltageand/or capacity requirements of the battery module 28, as well as theindividual voltage and capacity of each battery cell and the manner inwhich they are coupled. Accordingly, any number and/or arrangement ofbattery cells may be used depending on the desired power of the batterymodule 28 and/or the desired dimensions (e.g., length, width, and/orheight) of the battery module 28. It should be appreciated withreference to the illustrated embodiment that no actuating clampingfeatures are used on the battery module 28. Rather, the battery cellsremain in a compressed assembly by way of internal housing andcompression features that are not actuatable within the housing, asdiscussed below.

In this regard, the housing 62 of the battery module 28 may beconfigured such that a group of battery cells may be arranged within thehousing 62 as a compressed assembly to provide a desired power output,regardless of the degree of variance in dimensions of individual batterycells, as long as each are within the manufacturing tolerance of theindividual battery cells. As an example, at least one dimension of thehousing 62 may be selected to allow placement of a desired number ofbattery cells even if all of the battery cells have dimensions on alarger side of a manufacturing tolerance range. Further, the at leastone dimension of the housing 62 may be selected to place or maintain adesired compression force on the group of battery cells, even if all ofthe battery cells have dimensions on a smaller side of the manufacturingtolerance range. In this situation, the battery module 28 may includevarious internal features that ensure this force is provided.

For example, FIG. 4 illustrates an exploded perspective view of anembodiment of the battery module 28 including the housing 62 that issized to facilitate placement of a plurality of battery cells 90 in adesired manner (e.g., as a compressed assembly). While any single typeof battery cell 90 may be utilized, the battery cells 90 used in thebattery module 28 may all have the same general shape (e.g., prismatic,cylindrical, pouch, or any other), the same electrochemistry (e.g.,electrode active materials, electrolytes, additives), the same generaldimensions (e.g., to within manufacturing tolerances), and other similardesign features (e.g., electrical isolation). In the depictedembodiment, the battery module 28 includes a number of battery cells 90sufficient to enable the battery module 28 to provide a 48 V output,though the battery module 28 may output other voltages (e.g., 12 V)using different numbers and/or connections of battery cells 90.

The battery cells 90, before introduction into the module housing 62,may be arranged in a cell stack 92. In certain embodiments, a spacer 94(e.g., one or more) may be used between each battery cell 90 of the cellstack 92 to separate the battery cells 90 from one another. The spacers94 may be in any suitable form, such as discrete layers (e.g., plasticor silicone dividers) that are separate from the battery cells 90;adhesive strips, tabs, or the like that are adhered to the battery cells90; rubber bands wrapped around the individual battery cells 90; oradhesive foam tape secured to the battery cells 90. In embodiments wherethe spacers 94 are adhesive, the battery cells 90 may be adhered to oneanother.

In some embodiments, the spacers 94 may provide a sufficient degree ofelectrical insulation to prevent cell-to-cell conductance (e.g., due tocell swelling or movement). For example, in embodiments where a casing95 of the battery cells 90 is charged (e.g., used as a terminal), one ofthe spacers 94 may cover an entire conductive surface of a battery cell90 (e.g., the portions of the prismatic battery cells 90 that maycontact an adjacent battery cell 90). However, in other embodimentswhere the casings 95 are not charged, the spacers 94 (e.g., adhesivestrips, adhesive tabs, rubber bands, etc.) may only cover a portion ofthe conductive surfaces of the battery cells 90. In such embodiments,the spacers 94 may not necessarily provide electrical insulation. Inthese situations, an insulating material (e.g., an additional type ofspacer) may be disposed around the conductive surfaces of the batterycells 90.

By way of non-limiting example, the insulating material may be apolymeric coating, which may electrically insulate the battery cells 90and may protect the battery cells 90 from certain environmental (e.g.,air, moisture, debris, etc.) conditions. The polymeric coating may be adielectric capable of insulating the battery cells 90 from one anotherand also from other electrically conductive contacts (e.g., in portionsof the battery cell 90 where such insulation is desirable). Thepolymeric coating may be sprayed on the battery cell 90, or the batterycell 90 may be dipped in the polymeric coating. The polymeric coatingmay be a monomer or a cross-linkable resin that is either liquid inform, gelatinous, or in solution with a solvent that can be removed(e.g., by evaporation). The monomer or cross-linkable resin may then besubjected to an appropriate stimulus to affect some degree of hardeningof the polymeric coating to set the polymeric coating on the batterycell 90.

The cell stack 92 of battery cells 90 and spacers 94 (where utilized)may be inserted into an opening 96 of the housing 62. In certainembodiments, housing 62 may be sized to a maximum allowable tolerancefor a desired number of battery cells 90 (e.g., to provide a desiredpower output for the battery module 28). That is, the housing 62 may belarge enough to accommodate the desired number of battery cells 90 andother components (e.g., spacers 94), even if all of the battery cells 90are on the larger end of a manufacturing tolerance. This may bedesirable because the cell stack 92 may be assembled, compressed, andinserted into the housing 62 without first determining the degree ofvariance within the manufacturing tolerance of the individual batterycells 90. This may increase the speed and efficiency of manufacturingthe battery module 28.

In embodiments in which the battery cells 90 are all on the larger endof the manufacturing tolerance, the cell stack 92 of the battery cells90 and spacers 94 may fit tightly within the housing 62, which maymaintain a sufficient amount of compression force on the battery cells90. For instance, the cell stack 92 may be compressed (e.g., using anexternal actuating clamping mechanism that is not attached to or anintegral feature of the battery module 28) before the cell stack 92 isinserted into the housing 62. After the cell stack 92 is inserted intothe housing 62, the external clamping mechanism may be removed and thehousing 62 may itself maintain a desired compression on the batterycells 90 (e.g., may provide a compression force on the cell stack 92that is above a predetermined threshold). That is, the housing 62 mayreduce or block expansion of the battery cells 90 past a predeterminedthreshold. Thus, by compressing the cell stack 92 prior to inserting thecell stack 92 into the housing 62, the housing 62 may be used tomaintain a sufficient compression force on the battery cells 90 withoutusing actuating clamping mechanisms that remain with the battery module28 (e.g., internal and/or external to the housing 62). In situationswhere the battery cells 90 are appropriately sized (e.g., based on thedesired compression force and size of the cell stack 92), no additionalinternal compression maintenance may be used.

However, in some embodiments, the housing 62 may be sized such that agap is present between an interior surface 98 of the housing 62 and thecell stack 92 after the cell stack 92 is inserted. For example, this mayoccur in embodiments in which one or more of the battery cells 90 of thecell stack 92 are on the smaller end of the manufacturing tolerance. Tofill the gap and to maintain a sufficient compression force on the cellstack 92, one or more retaining walls 100 (e.g., removable retainingwalls) may be provided at ends 102 (e.g., a first end 105 and a secondend 107 opposite the first end 105) of the cell stack 92 to generate acompressed cell assembly 103. For example, the retaining walls 100 maybe generally rectangular prisms (e.g., blocks, plates) formed of anysuitable material or combination of materials, such as polymers havingdifferent degrees of hardness and/or strength, relatively compressiblematerials such as silicone, breakable and rigid materials such as glass,or composite materials such as glass-filed polypropylene. The retainingwalls 100 may be used to compress the cell stack 92 after the cell stackis inserted into the housing 62, or the cell stack 92 and/or theretaining walls 100 may be compressed together (e.g., as the compressedcell assembly 103) prior to insertion into the housing 62. For example,the compressed cell assembly 103 may be disposed in a portion 108 of thehousing defining an interior space of the housing 62, and the portion108 may surround the compressed cell assembly 103 on three sides. Inaddition, the retaining walls 100 may not necessarily be the same size,shape, or material, depending on their location within the batterymodule 28. Further, the present disclosure also encompasses embodimentswhere one or more actuating clamping mechanisms external or internal tothe housing 62 may be used in addition to the retaining walls 100 toprovide additional compression force on the battery cells 90. As shown,the battery module 28 may also include additional structures, such asone or more thermal gap pads 104, bus bars 106 configured toelectrically couple to the battery cells 90, or any other suitablecomponents. As discussed below, certain components of the battery module28 may be located on one or more of the retaining walls 100.

In the illustrated embodiment, the cell stack 92 is oriented along thez-axis 40 (e.g., in a row arrangement). However, it should be noted thatthe battery cells 90 may be positioned in any suitable arrangement. Forexample, while a single cell stack 92 may be utilized, in otherembodiments, the battery cells 90 may be arranged in one or more cellsstacks 92. Further, the one or more cell stacks 92 may be orientedvertically (e.g., in a columnar arrangement) or horizontally (e.g., in arow arrangement). For example, as illustrated in FIGS. 6-8, the batterymodule 28 may include a single cell stack 92, which may include anysuitable number of battery cells 90 and may be oriented horizontally. Inother embodiments, as illustrated in FIG. 9, the battery module 28 mayinclude two cell stacks 92 oriented vertically (e.g., in a columnararrangement), where each cell stack 92 may have half of the total numberof battery cells 90 in the battery module 28 and provide the samefunctionality (e.g., a 48V or other output).

The battery cells 90 described herein may be prismatic battery cells,where a prismatic battery cell, as defined herein, includes a prismaticcase that is generally rectangular in shape. In contrast to pouch cells,the prismatic casing is formed from a relatively inflexible, hard (e.g.,metallic) material. However, it should be noted that certain embodimentsdescribed below may incorporate pouch cells in addition to or in lieu ofprismatic battery cells. In accordance with present embodiments, eachprismatic battery cell may include a prismatic cell casing 110, asillustrated in FIG. 5. The prismatic cell casing 110 may include a topcasing portion 111, where a set of cell terminals 112 and 113 (e.g.,positive and negative cell terminals) are located. One or more cellvents 114 may also be located on the top casing portion 111. Theprismatic cell casing 110 also includes a bottom casing portion 115positioned opposite the top casing portion 111. First and second sides116 and 117, which may be straight or rounded, extend between the topand bottom casing portions 111 and 115 in respective positionscorresponding to the cell terminals 112 and 113. First and second faces118 and 119, which may be flat (as shown) or rounded, couple the firstand second sides 116 and 117 at opposing ends of each cell 90.

As illustrated in FIG. 6, which illustrates the battery module 28 ofFIG. 3 with the top portion 72 (e.g., top cover 73) removed, the batterymodule 28 includes two retaining walls 100 (e.g., blocks, plates)disposed against ends 102 of the cell stack 92. In particular, the tworetaining walls 100 include a first retaining wall 120 disposed againsta first end 122 of the cell stack 92 and a second retaining wall 124disposed against a second end 126 of the cell stack 92. As illustrated,the first and second retaining walls 120 and 122 may be generallyrectangular in shape. For example, the first and second retaining walls120 and 122 may include substantially rectangular and planar faces thatabut the first and second ends 122 and 126 of the cell stack 92. Incertain embodiments, the retaining walls 100 may be prismatic in shape,similar to the battery cells 90 used in the battery module 28. Incertain embodiments, the retaining walls 100 are not integrated into orcoupled to the housing 62.

The first and second retaining walls 120 and 124 may each include one ormore slots 128, which may be configured to receive a correspondingportion of a clamping and positioning mechanism to compress the cellstack 92 and insert the compressed cell stack 92 into the housing 62.For example, the one or more slots 128 may be configured to be engagedby a clamping mechanism for engagement and compression of the compressedcell assembly 103 prior to insertion into the housing 62. The clampingand positioning mechanism may be an actuating mechanism (e.g., a clamp)that is external to the battery module 28 and is removed from (e.g., isnot attached to) the battery module 28 after the cell stack 92 iscompressed and inserted into the housing 62. Thus, the clamping andpositioning mechanism is not an actuating clamping mechanism as intraditional systems because it is not coupled to or integrated with thebattery module 28. For example, it does not remain with the batterymodule 28 after manufacture. The first and second retaining walls 120and 124 also contact retaining tabs 130 of the housing 62 havinginterior surfaces 131 that are spaced apart by a fixed distance. Theretaining tabs 130 may create internal space within the housing 62 forother components (e.g., electronics, switches, conductors) of thebattery module 28. Additionally, the retaining tabs 130 are protrusionsin the housing 62 that include interior surfaces 131 that abut theremovable walls 120 and 124 to maintain the compressed state of the cellstack 92. In some embodiments, the interior surfaces 131 of theretaining tabs 130 may contact only a portion of the removable walls 120and 124. As such, after the cell stack 92 (e.g., as part of thecompressed cell assembly 103) is inserted into the housing 62, the firstand second retaining walls 120 and 124 and the retaining tabs 130 of thehousing 62 may provide a retaining and compression force on the batterycells 90 of the cell stack 92 such that the battery cells 90 may onlydecompress (e.g., expand) toward an uncompressed state by apredetermined amount. As such, the first and second retaining walls 120and 124 and the retaining tabs 130 (e.g., the interior surfaces 131 ofthe retaining tabs 130) may cooperate to maintain compression of thecell stack 92. Further, the interior surfaces 131 of the retaining tabs130 are configured to maintain the compressed cell assembly 103 in acompressed state having a compression force above a predeterminedthreshold. In certain embodiments, the first and second retaining walls120 and 124 and the retaining tabs 130 of the housing 62 may provide aretaining and compressing force on the battery cells 90 such that thebattery cells 90 do not decompress from the compressed state. Theretaining tabs 130 may also be used to maintain placement of one or morecomponents of the housing 62 (e.g., in embodiments in which the housing62 includes one or more separable portions). That is, a restorativeforce provided by the compressed cell assembly 103 against the housing62 may also be used as a force that maintains the relative position oftwo or more housing portions that would otherwise not couple together.

In other embodiments, the battery module 28 may include only a singleretaining wall 100, which may be disposed against the first end 122 orthe second end 126 of the cell stack 92. Providing only a singleretaining wall 100 may be desirable to decrease the dimensions of thehousing 62 and/or decrease manufacturing costs. The ability to use oneor two retaining walls also increases the dimensional flexibility of thehousing 62. In such embodiments, a clamping mechanism (e.g., that is notattached to the battery module 28 after the cell stack 92 is compressedand inserted into the housing 62) may engage the one or more slots 128of the single retaining wall 100 and may compress the cell stack 92between the single retaining wall 100 and a side of the cell stack 92opposite the retaining wall 100, or between the single retaining wall100 and the housing 62 (e.g., one of the retaining tabs 130 of thehousing 62).

Again, the removable walls 100 may be constructed of any suitablematerial, for example a plastic, composite, ceramics, silicone, glass,or glass-filled polypropylene. Indeed, it is presently recognized thatconstructing the retaining walls 100 from certain materials providesadvantages that have been heretofore unrecognized. For example,constructing the retaining walls 100 out of glass may facilitate therecycling of the battery module 28 by enabling their removal from thebattery module 28 without using complex equipment. Further, constructingthe spacers 100 out of glass or glass-filled polypropylene may bedesirable to provide a force-absorbing feature should the battery cells90 rupture and vent. The retaining walls 100 may, additionally oralternatively, include an intentional weak point or a crumple zone,which may provide similar force distribution.

For example, a battery cell 90 of the cell stack 92 may expand andrupture due to an internal overpressure or over-temperature of thebattery cell 90. Thermal runaway may also propagate to adjacent batterycells 90. To accommodate a resulting increase in the internal pressureof the battery module 28 itself, the retaining wall 100, an intentionalweak point or a crumple zone of the retaining wall 100, or a similarfeature, may be configured to break or crumple, which may consume someof the energy from the expanding or rupturing battery cell 90 and mayenable the expanding or rupturing battery cell 90 to expand intoadditional space in the housing 62. Present embodiments may provide amore efficient manner for accommodating such scenarios.

The vent gases caused by cell venting may be somewhat corrosive orotherwise deleterious to other components (e.g., the battery cells 90,electronics). The retaining walls 100 may incorporate a materialconfigured to mitigate certain undesirable chemical properties of thevent gas. For example, additional materials (e.g., absorptive,neutralizing) may be incorporated into the retaining walls 100.

In addition, or as an alternative, to using the retaining walls 100 inthe manner set forth above, the retaining walls 100 may be utilized as amount for one or more components of the battery module 28. For example,as illustrated in FIG. 7, the second removable wall 124 may be utilizedas a mount for a relay 132 of the battery module 28. A fan 134, portionsof a vent 136, and/or any other suitable components or electronics maybe similarly mounted on the second retaining wall 124. As such, thesecond retaining wall 124 separates the battery cells 90 from the relay132 and may block vented gases from the relay 132 and also block someheat transfer during normal operation. The second retaining wall 124 maybe any suitable shape and material construction to facilitate thecoupling of components of the battery module 28 to the second retainingwall 124. For example, in some embodiments, the second retaining wall124 may include a flat side surface 138 that may be used as a mount forthe desired components and a recess 140 shaped to accommodate the vent136 and/or other features.

Similarly, the retaining walls 100 may be utilized to mount both simpleand complex circuitry (e.g., electronics such as a battery controlmodule) of the battery module 28. For example, as illustrated in FIG. 8,the first retaining wall 120 may be used as a mount for a circuit board(e.g., control board) 150 of the battery module 28. Similar to thesecond retaining wall 124, the first retaining wall 120 may include anysuitable shape to facilitate the coupling of the circuit board 150 ofthe battery module 28 to the first retaining wall 120. For example, insome embodiments, the first retaining wall 120 may include a flat sidesurface 152 that may be used as a mount for the circuit board 150 and/orany other desired components of the battery module 28. In addition toproviding a structural mount for the circuit board 150, the firstretaining wall 120 may also thermally and electrically isolate thebattery cells 90 from the circuit board 150 and vice versa, which mayreduce noise (e.g., interference). Further, utilizing the firstretaining wall 120 and/or the second retaining wall 124 as mounts allowssubassembly of the desired components onto first retaining wall 120and/or the second retaining wall 124 prior to inserting the firstretaining wall 120 and/or the second retaining wall 124 into the housing62, which may decrease manufacturing times and costs. In other words,the retaining walls 120 and 124 shown in FIGS. 7 and 8 having theirmounted components could be introduced in assembled form into thebattery module 28, which would greatly decrease manufacturing complexityand time.

As noted above, the battery module 28 may, in some embodiments, includeonly a single retaining wall 100. In such embodiments, the retainingwall 100 may be used to mount several desired components of the batterymodule 28, such as the circuit board 150, the relay 132, the fan 134,and/or the vent 136. As an example, it may be desirable to utilize asingle retaining wall 100 to reduce the size of the housing 62 and/or toreduce manufacturing costs. Indeed, for battery modules 28 where thefootprint of the battery module 28 is of concern, such mounting mayafford a degree of flexibility that eases manufacturing considerations.

The orientation of the retaining walls 100 is not limited to theorientations shown in FIGS. 6-8. Rather, the present disclosure alsoincludes alternative orientations, as shown in FIG. 9. Further, a singleretaining wall 100 may be used to retain multiple cell stacks 92. Forexample, as illustrated in FIG. 9, the battery cells 90 may be arrangedinto two (or more) cell stacks 92. In the illustrated embodiment, thetwo cell stacks 92 include a first columnar cell stack 170 and a secondcolumnar cell stack 172. However, in other embodiments, more than twocell stacks 92 may be utilized and/or the cell stacks 92 may bepositioned horizontally (e.g., in a row arrangement).

A retaining wall 100 may be disposed on a top surface 174 of the firstand second columnar cell stacks 170 and 172. In some embodiments, theretaining wall 100 may include the one or more slots 128 configured tobe engaged by a clamping mechanism, as discussed above. The first andsecond columnar cell stacks 170 and 172 may be compressed using theretaining wall 100 and inserted into the housing 62 of the batterymodule 28. In particular, a first portion of a clamping mechanism mayabut the top surface 174 of the first and second columnar cell stacks170 and 172 and a second portion of the clamping mechanism may beinserted into the one or more slots 128 of the retaining wall 100. Theclamping mechanism may apply a compressive force against the top surface174 of the first and second columnar cell stacks 170 and 172 and theretaining wall 100. The retaining wall 100 may be retained in place bythe top portion 72 of the housing 62. However, in other embodiments, thefirst and second columnar cell stacks 170 and 172 may be compressedusing two retaining walls 100 disposed about the top surface 174 and abottom surface 176 of the first and second columnar cells stacks 170 and172, respectively.

Additionally, in some embodiments, the retaining wall 100 may functionas a portion of the housing 62 of the battery module 28. For example, asillustrated in FIG. 10, a center region 178 of the top portion 72 of thehousing 62 is removed. The first and second columnar cell stacks 170 and172 may be compressed and inserted into the housing 62 using theretaining wall 100 as discussed above. However, in FIG. 10, a topsurface 180 of the retaining wall 100 may be exposed and may function asthe removed center region 178 of the top portion 72 of the housing 62.In such embodiments, the retaining wall 100 may be retained within thehousing via retaining tabs 182 of the housing 62.

Again, in a similar manner as set forth above with respect to theretaining walls 120, 124 of FIGS. 6-8, the removable wall 100 of FIGS. 9and 10 may have various conductors, switches (e.g., relays), andelectronics (e.g., battery control module, sensors, a printed circuitboard) mounted to it. In the illustrated embodiment of FIG. 10, thebattery module 28 includes a substantially isolated region 190 formed bythe top portion 72 of the housing 62 (functioning as the tabs 182), theremovable wall 100, peripheral walls 192 of the top portion 72, and aremovable top cover (not shown) that fits over the peripheral walls 192(e.g., similar to top cover 73 of FIG. 3). The substantially isolatedregion may isolate the electronics, switches, circuits, and so forth(e.g., electrical components) mounted to the removable wall 100 from aregion of the battery module 28 housing the battery cells 90, as well asfrom the external environment.

FIG. 11 illustrates an embodiment of a method 200 for manufacturing thebattery modules 28 of the present approach. In particular, the method200 includes assembling a plurality of battery cells (e.g., the batterycells 90) into a cell stack (e.g., the cell stack 92) (block 202). Incertain embodiments, assembling the plurality of battery cells into thecell stack may include providing a cell spacer (e.g., spacer 94) betweeneach battery cell of the plurality of battery cells. As described indetail above, the spacers 94 may electrically insulate the battery cellsfrom one another.

Further, the method 200 includes compressing the cell stack into acompressed cell stack (block 204). Compressing the cell stack into thecompressed cell stack may utilize one or more retaining walls 100, asdiscussed in detail above, that may be configured to be engaged by aclamping mechanism. In some embodiments, the cell stack 92 may becompressed between two retaining walls 100 using the clamping mechanism.For example, the clamping mechanism may include a first clamp configuredto engage with a first retaining wall 100 (e.g., via the one or moreslots 128) and a second clamp configured to engage with a secondretaining wall 100 (e.g., via the one or more slots 128). In otherembodiments, the cell stack 92 may be compressed between a retainingwall 100 disposed about a first end of the cell stack 92 and a surfaceof one of the battery cells 90 disposed at a second end of the cellstack 92. In such embodiments, the clamping mechanism may include afirst clamp configured to engage the retaining wall 100 (e.g., via theone or more slots) and a second clamp configured to engage with thesurface of the battery cell 90 disposed at the second end of the cellstack 92. Alternatively, the cell stack 92 may be compressed between aretaining wall 100 disposed about a first end of the cell stack 92 andan interior surface of the housing 62 disposed about a second (e.g.,opposite) end of the cell stack 92. In such embodiments, the clampingmechanism may include a first clamp configured to engage with theretaining wall 100 (e.g., via the one or more slots 128) and a secondclamp configured to engage with the housing 62 (e.g., an exteriorsurface of the housing 62). An example embodiment of this arrangement isshown in FIG. 12.

Once the compressed cell stack is formed, the compressed cell stack 92is inserted into the housing 62 of the battery module 28 (block 206). Asdiscussed in detail above, the one or more retaining walls 100 incombination with the housing 62 may provide a sufficient retention andcompression force on the compressed cell stack to retain the compressedcell stack in a desired position and to reduce or prevent expansion ofthe battery cells during operation of the battery module 28. Further, asnoted above, the clamping mechanism may be external to the batterymodule 28 and may be removed from the battery module (e.g., may not beattached to the battery module 28) after the cell stack 92 is compressedand inserted into the housing 62.

FIG. 12 illustrates a partial schematic view of a system 230 that may beconfigured to implement the method 200 to manufacture the disclosedbattery modules 28. As illustrated, the cell assembly 103 may beassembled using the battery cells 90, the spacers 94, and one or moreretaining walls 100. As described above, the retaining walls 100 includethe one or more slots 128. A clamping and positioning system 232 may beconfigured to engage the one or more slots 128 of the one or moreretaining walls 100 and/or a surface of a battery cell 90 on an end 102of the cell stack 92 (e.g., for embodiments in which only one removablewall 100 is used). The clamping and positioning system 232 may beconfigured to compress the cell assembly 103 and to insert thecompressed cell assembly 103 within the housing 62 of the battery module28.

FIG. 13 illustrates a schematic view of the battery module 28 includingtwo retaining walls 100 (e.g., the first and second retaining walls 120and 124). As illustrated, the battery cells 90 (and, in someembodiments, the cell spacers 94) are arranged into the cell stack 92.As described in detail above, the first and second retaining walls 120and 124 (and one or more additional retaining walls 100, when needed)may be disposed adjacent to the ends 102 of the cell stack 92 andcompressed to form the compressed cell assembly 103, and the compressedcell assembly 103 may be inserted into the housing 62. In addition, oneor more additional retaining walls 100 and/or spacers 94 may be providedif a gap is present between one or more ends 250 of the compressed cellassembly 103 and the retaining tabs 130 of the housing 62 (e.g., if alength 252 of the cell assembly 103 including the first and secondretaining walls 120 and 124 is less than a distance 254 between theretaining tabs 130 at opposing ends of the housing 62).

As illustrated, a gap 256 is present between the first retaining wall120 and the end portion 64 of the housing 62. Similarly, a gap 258 ispresent between the second retaining wall 124 and the end portion 66 ofthe housing 62. The restorative force resulting from internal pressures(e.g., internal battery cell pressures) of the compressed cell assembly103 may cause the compressed cell assembly 103 to expand (e.g.,decompress) in outward directions 260 (e.g., along the Z axis 40)against the housing 62 (e.g., against retaining tabs 130). The retainingtabs 130 maintain the position of the first and second retaining walls120 and 124 (and any additional retaining walls 100) such that the firstand second retaining walls 120 and 124 do not move past the retainingtabs 130 and into the gaps 256 and 258, respectively. By maintaining theposition of the first and second retaining walls 120 and 234, thecompressed cell assembly 103 remains in a compressed state with acompression force above a predetermined threshold. The predeterminedthreshold may be based on, for example, a correlation between cellvolume, expansion, or swell percentage, and state of charge (SOC) forthe particular type of battery cells utilized.

As noted above, a battery cell 90 of the cell stack 92 may expand andrupture due to an internal overpressure or over-temperature of thebattery cell 90. To accommodate a resulting increase in the internalpressure of the battery module 28 itself, the first and second retainingwalls 120 and 124, an intentional weak point or a crumple zone of thefirst and second retaining walls 120 and 124, or a similar feature, maybe configured to break or crumple. This may consume some of the energyfrom the expanding or rupturing battery cell 90. For example, if thefirst retaining walls 120 breaks or crumples, portions of the firstretaining wall 120 may fall into the gap 256, which may create spacebetween the end of the cell stack 92 and the retaining tabs 130. Thisadditional space may allow the battery cells 90 to expand and/orseparate, which may reduce impact on other components of the battermodule 28. Additionally, the battery cells 90 may expand or swell intothe gap 256. Further, if the first retaining wall 120 breaks orcrumples, at least a portion of the gap 256 may be exposed to thebattery cells 90, and the vented gases may spread to the gap 256, whichmay reduce the exposure of the adjacent battery cells 90 to the ventedgases.

In certain embodiments, one or more retaining walls 100 may function asan end portion (e.g., the end portions 64 or 66, the side portions 68 or70, the top portion 72, or the bottom portion 74) of the housing 62. Forexample, as illustrated in FIG. 14, the housing 62 does not include theend portion 66. That is, the housing 62 may be constructed using the endportion 64, the side portions 68 and 70, the top portion 72, the bottomportion 74, and the retaining tabs 130, and the housing 62 may notinclude the end portion 66. Instead, a retaining wall 100 (e.g., thesecond retaining wall 124) may be used as the end portion 66. Thus, anend 250 of the compressed cell assembly 103 (e.g., an exterior surface270 of the second retaining wall 124) may be an exterior surface of thehousing 62. As described above, the position of the second retainingwall 124 is maintained by the retaining tabs 130 and the restorativeforce of the compressed cell assembly 103 expanding from a morecompressed stage. As such, the retaining tabs 130 maintain thecompressed state of the compressed cell assembly 130 and enable thesecond retaining wall 124 to be used as an end portion of the housing62.

One or more of the disclosed embodiments, alone or on combination, mayprovide one or more technical effects including the manufacture ofbattery modules having compressed battery cells (e.g., prismatic batterycells). The disclosed designs enable the use of stacks of battery cellsthat may be placed within a housing of the battery module and that maybe compressed and/or restrained within the housing of the battery moduleusing one or more spacers. The disclosed battery module designs enablegreater variability in the dimensions of each battery cell of a batterymodule, providing greater flexibility to select a set of battery cellsfor installation in a battery module based on particular electrical andthermal considerations, without having to worry about the exactdimensions of each battery cell relative to the battery module housing.Additionally, the disclosed spacers may reduce or prevent swelling ofthe battery cells of the battery module during operation, thus improvingperformance of the battery cells over the lifetime of the batterymodule. Further, the spacers may provide thermal runaway protection.Additionally, the spacers may function as a structural mount forcomponents of the battery module, such as the relay and the circuitboard, and may electrically and thermally isolate the battery cells fromthe circuit board. Accordingly, the disclosed battery module designsoffer improved flexibility and performance compared to other batterymodule designs. Additionally, the disclosed battery module designs mayreduce weight and bulk of the battery modules, because no actuatingclamping mechanisms are incorporated into (e.g., attached to, integratedinto, disposed within) the battery module. The technical effects andtechnical problems in the specification are exemplary and are notlimiting. It should be noted that the embodiments described in thespecification may have other technical effects and can solve othertechnical problems.

While only certain features and embodiments have been illustrated anddescribed, many modifications and changes may occur to those skilled inthe art (e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters (e.g.,temperatures, pressures, etc.), mounting arrangements, use of materials,colors, orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter. The order or sequence ofany process or method steps may be varied or re-sequenced according toalternative embodiments. It is, therefore, to be understood that theappended claims are intended to cover all such modifications and changesas fall within the true spirit of the invention. Furthermore, in aneffort to provide a concise description of the exemplary embodiments,all features of an actual implementation may not have been described. Itshould be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation specific decisions may be made. Such a development effortmight be complex and time consuming, but would nevertheless be a routineundertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure, without undueexperimentation.

1. A method of manufacturing a battery module, comprising: assembling aplurality of prismatic battery cells of the battery module into a cellstack; compressing the cell stack using an actuating clamping mechanism;inserting the cell stack into a housing of the battery module with theactuating clamping mechanism engaged with and compressing the cellstack; and removing the actuating clamping mechanism from the cell stackto yield the battery module, wherein the housing of battery modulemaintains a compression of the cell stack above a predeterminedthreshold after removing the actuating clamping mechanism.
 2. The methodof claim 1, wherein compressing the cell stack comprises: disposing afirst retaining wall against a first end of the cell stack, wherein thefirst retaining wall comprises a first slot; and inserting a first clampof the actuating clamping mechanism into the first slot of the firstretaining wall to engage the first end of the cell stack.
 3. The methodof claim 2, wherein compressing the cell stack comprises: disposing asecond retaining wall against a second end of the cell stack oppositethe first end, wherein the second retaining wall comprises a secondslot; and inserting a second clamp of the actuating clamping mechanisminto the second slot of the second retaining wall to engage the secondend of the cell stack.
 4. The method of claim 1, wherein assembling theplurality of prismatic battery cells into the cell stack comprisesinserting an electrically insulating cell spacer between each of theplurality of prismatic battery cells in the cell stack.
 5. The method ofclaim 1, wherein assembling the plurality of prismatic battery cellscomprises assembling the plurality of prismatic battery cells into ahorizontal cell stack.
 6. A method of manufacturing a battery module,comprising: assembling a plurality of prismatic battery cells of thebattery module into a cell stack having a first end and a second endopposite the first end; disposing a first retaining wall against thefirst end of the cell stack, wherein the first retaining wall comprisesa first slot; engaging the cell stack with an actuating clampingmechanism, comprising: inserting a first clamp of an actuating clampingmechanism into the first slot of the first retaining wall; compressingthe cell stack using the actuating clamping mechanism; inserting thecell stack into a housing of the battery module while the cell stack iscompressed by the actuating clamping mechanism; and removing theactuating clamping mechanism from the cell stack while the cell stack isin the housing to yield the battery module, comprising: withdrawing thefirst clamp of the actuating clamping mechanism from the first slot ofthe first retaining wall, wherein the housing of battery modulemaintains a compression of the cell stack above a predeterminedthreshold after removing the actuating clamping mechanism.
 7. The methodof claim 6, wherein disposing the first retaining wall against the firstend of the cell stack comprises disposing a first surface of the firstretaining wall against the first end of the cell stack, wherein thefirst retaining wall comprises a second surface opposite the firstsurface.
 8. The method of claim 7, comprising mounting a circuit boardto the second surface of the first retaining wall before inserting thecell stack into the housing of the battery module.
 9. The method ofclaim 7, comprising mounting a relay to the second surface of the firstretaining wall before inserting the cell stack into the housing of thebattery module.
 10. The method of claim 7, comprising mounting a fan tothe second surface of the first retaining wall before inserting the cellstack into the housing of the battery module.
 11. The method of claim 7,comprising mounting a vent to the second surface of the first retainingwall before inserting the cell stack into the housing of the batterymodule.
 12. The method of claim 6, wherein the first retaining wallcomprises a crumple zone configured to deform before the housing of thebattery module in response to expansion of the cell stack duringoperation of the battery module.
 13. The method of claim 6, whereininserting the cell stack into the housing of the battery modulecomprises disposing the first retaining wall against first alignmenttabs that extend from a first interior surface of the housing.
 14. Themethod of claim 6, wherein, after inserting the cell stack into thehousing of the battery module, the first retaining wall is securedagainst the housing by only the compression without being fastened tothe housing.
 15. The method of claim 6, wherein assembling the pluralityof prismatic battery cells comprises assembling the plurality ofprismatic battery cells into a horizontal cell stack comprising twoadjacent columns of prismatic battery cells.
 16. The method of claim 6,comprising providing the first retaining wall, wherein the firstretaining wall comprises glass.
 17. The method of claim 16, wherein thefirst retaining wall consists essentially of glass.
 18. The method ofclaim 6, comprising disposing a second retaining wall against the secondend of the cell stack prior to compressing the cell stack, wherein thesecond retaining wall comprises a second slot.
 19. The method of claim18, wherein inserting the cell stack into the housing of the batterymodule comprises disposing the second retaining wall against secondalignment tabs that extend from a second interior surface of the housingopposite the first.
 20. The method of claim 18, wherein engaging thecell stack with an actuating clamping mechanism comprises inserting asecond clamp of the actuating clamping mechanism into the second slot ofthe second retaining wall, and wherein removing the actuating clampingmechanism comprises removing the second clamp of the actuating clampingmechanism from the second slot of the second retaining wall.
 21. Amethod of manufacturing a battery module, comprising: assembling aplurality of prismatic battery cells of the battery module into a cellstack having a first end and a second end opposite the first end;disposing a first retaining wall against the first end of the cell stackand a second retaining wall against the second end of the cell stack,wherein the first retaining wall comprises a first slot and the secondretaining wall comprises a second slot; inserting a first clamp of anactuating clamping mechanism into the first slot of the first retainingwall and a second clamp of the actuating clamping mechanism into thesecond slot of the second retaining wall; compressing the cell stackusing the actuating clamping mechanism; inserting the cell stack into ahousing of the battery module while the cell stack is compressed by theactuating clamping mechanism; and withdrawing the first clamp of theactuating clamping mechanism from the first slot of the first retainingwall and the second clamp of the actuating clamping mechanism from thesecond slot of the second retaining wall to yield the battery module,wherein the housing of the battery module maintains a compression of thecell stack above a predetermined threshold after withdrawing the firstclamp and the second clamp of the actuating clamping mechanism.
 22. Themethod of claim 21, wherein inserting the cell stack comprises insertingthe cell stack into the housing such that the housing surrounds andcontacts only three sides of the cell assembly.
 23. The method of claim21, wherein, after inserting the cell stack into the housing of thebattery module, the first and second retaining walls are secured to thehousing by only the compression without being fastened to the housing.